I agree with Arkon's assessment - something very fishy happened here. Has there been any response? This is quite disturbing. This "cheat / bug" was relatively obvious to catch, but if someone can add just $2 to a couple countries it would be much more difficult to notice and could turn the tide of a close battle. I'd like to hear from the developers on this.
FYI - I sent a private message to Inna, ask for him too examine the issue. He sent back the following message:
Actually some cheating can be possible only in playing against AI.
But I'll discuss this issue with our programmers
EDITED TO REFLECT INNA'S REPLY BELOW